X-Git-Url: https://gerrit.automotivelinux.org/gerrit/gitweb?a=blobdiff_plain;f=src%2Fjobs.c;h=aa014f3a4b94bd2b525aca8ef4eedb9cf215c4f8;hb=b612db216c2793c34e264254794db3308d20d796;hp=c4f32244fc67767f42c3c4bac60873930a43e45b;hpb=feccdb76f572a5fad947475c21b5b9aff696b04b;p=src%2Fapp-framework-binder.git

diff --git a/src/jobs.c b/src/jobs.c
index c4f32244..aa014f3a 100644
--- a/src/jobs.c
+++ b/src/jobs.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2016, 2017 "IoT.bzh"
+ * Copyright (C) 2016-2019 "IoT.bzh"
  * Author José Bollo <jose.bollo@iot.bzh>
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -18,327 +18,906 @@
 #define _GNU_SOURCE
 
 #include <stdlib.h>
+#include <stdint.h>
 #include <unistd.h>
 #include <signal.h>
+#include <string.h>
 #include <time.h>
 #include <sys/syscall.h>
 #include <pthread.h>
 #include <errno.h>
 #include <assert.h>
+#include <sys/eventfd.h>
+
+#include <systemd/sd-event.h>
 
 #include "jobs.h"
+#include "evmgr.h"
 #include "sig-monitor.h"
 #include "verbose.h"
+#include "systemd.h"
 
-/* control of threads */
-struct thread
+#define EVENT_TIMEOUT_TOP  	((uint64_t)-1)
+#define EVENT_TIMEOUT_CHILD	((uint64_t)10000)
+
+/** Internal shortcut for callback */
+typedef void (*job_cb_t)(int, void*);
+
+/** starting mode for jobs */
+enum start_mode
 {
-	pthread_t tid;     /* the thread id */
-	unsigned stop: 1;  /* stop request */
-	unsigned ended: 1; /* ended status */
-	unsigned works: 1; /* is it processing a job? */
+	Start_Default,  /**< Start a thread if more than one jobs is pending */
+	Start_Urgent,   /**< Always start a thread */
+	Start_Lazy      /**< Never start a thread */
 };
 
-/* describes pending job */
+/** Description of a pending job */
 struct job
 {
-	struct job *next;   /* link to the next job enqueued */
-	void *group;        /* group of the request */
-	void (*callback)(int,void*,void*,void*);     /* processing callback */
-	void *arg1;         /* first arg */
-	void *arg2;         /* second arg */
-	void *arg3;         /* second arg */
-	int timeout;        /* timeout in second for processing the request */
-	int blocked;        /* is an other request blocking this one ? */
+	struct job *next;    /**< link to the next job enqueued */
+	const void *group;   /**< group of the request */
+	job_cb_t callback;   /**< processing callback */
+	void *arg;           /**< argument */
+	int timeout;         /**< timeout in second for processing the request */
+	unsigned blocked: 1; /**< is an other request blocking this one ? */
+	unsigned dropped: 1; /**< is removed ? */
+};
+
+/** Description of threads */
+struct thread
+{
+	struct thread *next;   /**< next thread of the list */
+	struct thread *upper;  /**< upper same thread */
+	struct thread *nholder;/**< next holder for evloop */
+	pthread_cond_t *cwhold;/**< condition wait for holding */
+	struct job *job;       /**< currently processed job */
+	pthread_t tid;         /**< the thread id */
+	volatile unsigned stop: 1;      /**< stop requested */
+	volatile unsigned waits: 1;     /**< is waiting? */
+	volatile unsigned leaved: 1;    /**< was leaved? */
+};
+
+/**
+ * Description of synchronous callback
+ */
+struct sync
+{
+	struct thread thread;	/**< thread loop data */
+	union {
+		void (*callback)(int, void*);	/**< the synchronous callback */
+		void (*enter)(int signum, void *closure, struct jobloop *jobloop);
+				/**< the entering synchronous routine */
+	};
+	void *arg;		/**< the argument of the callback */
 };
 
 /* synchronisation of threads */
 static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
 static pthread_cond_t  cond = PTHREAD_COND_INITIALIZER;
 
+/* counts for threads */
+static int allowed_thread_count = 0; /** allowed count of threads */
+static int started_thread_count = 0; /** started count of threads */
+static int busy_thread_count = 0;    /** count of busy threads */
+
+/* list of threads */
+static struct thread *threads;
+static _Thread_local struct thread *current_thread;
+
+/* counts for jobs */
+static int remaining_job_count = 0;  /** count of job that can be created */
+static int allowed_job_count = 0;    /** allowed count of pending jobs */
+
 /* queue of pending jobs */
-static struct job *first_job = NULL;
+static struct job *first_pending_job;
+static struct job *first_free_job;
 
-/* count allowed, started and running threads */
-static int allowed = 0;
-static int started = 0;
-static int running = 0;
-static int remains = 0;
+/* event loop */
+static struct evmgr *evmgr;
 
-/* list of threads */
-static struct thread *threads = NULL;
+static void (*exit_handler)();
 
-/* add the job to the list */
-static inline void job_add(struct job *job)
+/**
+ * Create a new job with the given parameters
+ * @param group    the group of the job
+ * @param timeout  the timeout of the job (0 if none)
+ * @param callback the function that achieves the job
+ * @param arg      the argument of the callback
+ * @return the created job unblock or NULL when no more memory
+ */
+static struct job *job_create(
+		const void *group,
+		int timeout,
+		job_cb_t callback,
+		void *arg)
 {
-	void *group = job->group;
+	struct job *job;
+
+	/* try recyle existing job */
+	job = first_free_job;
+	if (job)
+		first_free_job = job->next;
+	else {
+		/* allocation without blocking */
+		pthread_mutex_unlock(&mutex);
+		job = malloc(sizeof *job);
+		pthread_mutex_lock(&mutex);
+		if (!job) {
+			ERROR("out of memory");
+			errno = ENOMEM;
+			goto end;
+		}
+	}
+	/* initialises the job */
+	job->group = group;
+	job->timeout = timeout;
+	job->callback = callback;
+	job->arg = arg;
+	job->blocked = 0;
+	job->dropped = 0;
+end:
+	return job;
+}
+
+/**
+ * Adds 'job' at the end of the list of jobs, marking it
+ * as blocked if an other job with the same group is pending.
+ * @param job the job to add
+ */
+static void job_add(struct job *job)
+{
+	const void *group;
 	struct job *ijob, **pjob;
 
-	pjob = &first_job;
-	ijob = first_job;
-	group = job->group ? : job;
+	/* prepare to add */
+	group = job->group;
+	job->next = NULL;
+
+	/* search end and blockers */
+	pjob = &first_pending_job;
+	ijob = first_pending_job;
 	while (ijob) {
-		if (ijob->group == group)
+		if (group && ijob->group == group)
 			job->blocked = 1;
 		pjob = &ijob->next;
 		ijob = ijob->next;
 	}
+
+	/* queue the jobs */
 	*pjob = job;
-	job->next = NULL;
-	remains--;
+	remaining_job_count--;
 }
 
-/* get the next job to process or NULL if none */
+/**
+ * Get the next job to process or NULL if none.
+ * @return the first job that isn't blocked or NULL
+ */
 static inline struct job *job_get()
 {
-	struct job *job, **pjob;
-	pjob = &first_job;
-	job = first_job;
-	while (job && job->blocked) {
-		pjob = &job->next;
+	struct job *job = first_pending_job;
+	while (job && job->blocked)
 		job = job->next;
+	if (job)
+		remaining_job_count++;
+	return job;
+}
+
+/**
+ * Releases the processed 'job': removes it
+ * from the list of jobs and unblock the first
+ * pending job of the same group if any.
+ * @param job the job to release
+ */
+static inline void job_release(struct job *job)
+{
+	struct job *ijob, **pjob;
+	const void *group;
+
+	/* first unqueue the job */
+	pjob = &first_pending_job;
+	ijob = first_pending_job;
+	while (ijob != job) {
+		pjob = &ijob->next;
+		ijob = ijob->next;
 	}
-	if (job) {
-		*pjob = job->next;
-		remains++;
+	*pjob = job->next;
+
+	/* then unblock jobs of the same group */
+	group = job->group;
+	if (group) {
+		ijob = job->next;
+		while (ijob && ijob->group != group)
+			ijob = ijob->next;
+		if (ijob)
+			ijob->blocked = 0;
 	}
-	return job;
+
+	/* recycle the job */
+	job->next = first_free_job;
+	first_free_job = job;
 }
 
-/* unblock a group of job */
-static inline void job_unblock(void *group)
+/**
+ * Monitored cancel callback for a job.
+ * This function is called by the monitor
+ * to cancel the job when the safe environment
+ * is set.
+ * @param signum 0 on normal flow or the number
+ *               of the signal that interrupted the normal
+ *               flow, isn't used
+ * @param arg    the job to run
+ */
+__attribute__((unused))
+static void job_cancel(int signum, void *arg)
 {
-	struct job *job;
+	struct job *job = arg;
+	job->callback(SIGABRT, job->arg);
+}
 
-	job = first_job;
-	while (job) {
-		if (job->group == group) {
-			job->blocked = 0;
-			break;
+/**
+ * wakeup the event loop if needed by sending
+ * an event.
+ */
+static void evloop_wakeup()
+{
+	if (evmgr)
+		evmgr_wakeup(evmgr);
+}
+
+/**
+ * Release the currently held event loop
+ */
+static void evloop_release()
+{
+	struct thread *nh, *ct = current_thread;
+
+	if (ct && evmgr && evmgr_release_if(evmgr, ct)) {
+		nh = ct->nholder;
+		ct->nholder = 0;
+		if (nh) {
+			evmgr_try_hold(evmgr, nh);
+			pthread_cond_signal(nh->cwhold);
 		}
-		job = job->next;
 	}
 }
 
-/* call the job */
-static inline void job_call(int signum, void *arg)
+/**
+ * get the eventloop for the current thread
+ */
+static int evloop_get()
 {
-	struct job *job = arg;
-	job->callback(signum, job->arg1, job->arg2, job->arg3);
+	return evmgr && evmgr_try_hold(evmgr, current_thread);
 }
 
-/* cancel the job */
-static inline void job_cancel(int signum, void *arg)
+/**
+ * acquire the eventloop for the current thread
+ */
+static void evloop_acquire()
 {
-	struct job *job = arg;
-	job->callback(SIGABRT, job->arg1, job->arg2, job->arg3);
+	struct thread *pwait, *ct;
+	pthread_cond_t cond;
+
+	/* try to get the evloop */
+	if (!evloop_get()) {
+		/* failed, init waiting state */
+		ct = current_thread;
+		ct->nholder = NULL;
+		ct->cwhold = &cond;
+		pthread_cond_init(&cond, NULL);
+
+		/* queue current thread in holder list */
+		pwait = evmgr_holder(evmgr);
+		while (pwait->nholder)
+			pwait = pwait->nholder;
+		pwait->nholder = ct;
+
+		/* wake up the evloop */
+		evloop_wakeup();
+
+		/* wait to acquire the evloop */
+		pthread_cond_wait(&cond, &mutex);
+		pthread_cond_destroy(&cond);
+	}
+}
+
+/**
+ * Enter the thread
+ * @param me the description of the thread to enter
+ */
+static void thread_enter(volatile struct thread *me)
+{
+	evloop_release();
+	/* initialize description of itself and link it in the list */
+	me->tid = pthread_self();
+	me->stop = 0;
+	me->waits = 0;
+	me->leaved = 0;
+	me->nholder = 0;
+	me->upper = current_thread;
+	me->next = threads;
+	threads = (struct thread*)me;
+	current_thread = (struct thread*)me;
 }
 
-/* main loop of processing threads */
-static void *thread_main_loop(void *data)
+/**
+ * leave the thread
+ * @param me the description of the thread to leave
+ */
+static void thread_leave()
+{
+	struct thread **prv, *me;
+
+	/* unlink the current thread and cleanup */
+	me = current_thread;
+	prv = &threads;
+	while (*prv != me)
+		prv = &(*prv)->next;
+	*prv = me->next;
+
+	current_thread = me->upper;
+}
+
+/**
+ * Main processing loop of internal threads with processing jobs.
+ * The loop must be called with the mutex locked
+ * and it returns with the mutex locked.
+ * @param me the description of the thread to use
+ * TODO: how are timeout handled when reentering?
+ */
+static void thread_run_internal(volatile struct thread *me)
 {
-	struct thread *me = data;
 	struct job *job;
 
-	me->works = 0;
-	me->ended = 0;
-	sig_monitor_init_timeouts();
-	pthread_mutex_lock(&mutex);
+	/* enter thread */
+	thread_enter(me);
+
+	/* loop until stopped */
 	while (!me->stop) {
+		/* release the current event loop */
+		evloop_release();
+
 		/* get a job */
 		job = job_get();
-		if (job == NULL && first_job != NULL && running == 0) {
-			/* sad situation!! should not happen */
-			ERROR("threads are blocked!");
-			job = first_job;
-			first_job = job->next;
-		}
-		if (job == NULL) {
-			/* no job... */
-			pthread_cond_wait(&cond, &mutex);
-		} else {
+		if (job) {
+			/* prepare running the job */
+			job->blocked = 1; /* mark job as blocked */
+			me->job = job; /* record the job (only for terminate) */
+
 			/* run the job */
-			running++;
-			me->works = 1;
 			pthread_mutex_unlock(&mutex);
-			sig_monitor(job->timeout, job_call, job);
+			sig_monitor(job->timeout, job->callback, job->arg);
 			pthread_mutex_lock(&mutex);
-			me->works = 0;
-			running--;
-			if (job->group != NULL)
-				job_unblock(job->group);
-			free(job);
-		}
 
+			/* release the run job */
+			job_release(job);
+		/* no job, check event loop wait */
+		} else if (evloop_get()) {
+			if (!evmgr_can_run(evmgr)) {
+				/* busy ? */
+				CRITICAL("Can't enter dispatch while in dispatch!");
+				abort();
+			}
+			/* run the events */
+			evmgr_prepare_run(evmgr);
+			pthread_mutex_unlock(&mutex);
+			sig_monitor(0, (void(*)(int,void*))evmgr_job_run, evmgr);
+			pthread_mutex_lock(&mutex);
+		} else {
+			/* no job and no event loop */
+			busy_thread_count--;
+			if (!busy_thread_count)
+				ERROR("Entering job deep sleep! Check your bindings.");
+			me->waits = 1;
+			pthread_cond_wait(&cond, &mutex);
+			me->waits = 0;
+			busy_thread_count++;
+		}
 	}
-	me->ended = 1;
-	pthread_mutex_unlock(&mutex);
+	/* cleanup */
+	evloop_release();
+	thread_leave();
+}
+
+/**
+ * Main processing loop of external threads.
+ * The loop must be called with the mutex locked
+ * and it returns with the mutex locked.
+ * @param me the description of the thread to use
+ */
+static void thread_run_external(volatile struct thread *me)
+{
+	/* enter thread */
+	thread_enter(me);
+
+	/* loop until stopped */
+	me->waits = 1;
+	while (!me->stop)
+		pthread_cond_wait(&cond, &mutex);
+	me->waits = 0;
+	thread_leave();
+}
+
+/**
+ * Root for created threads.
+ */
+static void thread_main()
+{
+	struct thread me;
+
+	busy_thread_count++;
+	started_thread_count++;
+	sig_monitor_init_timeouts();
+	thread_run_internal(&me);
 	sig_monitor_clean_timeouts();
-	return me;
+	started_thread_count--;
+	busy_thread_count--;
+}
+
+/**
+ * Entry point for created threads.
+ * @param data not used
+ * @return NULL
+ */
+static void *thread_starter(void *data)
+{
+	pthread_mutex_lock(&mutex);
+	thread_main();
+	pthread_mutex_unlock(&mutex);
+	return NULL;
 }
 
-/* start a new thread */
+/**
+ * Starts a new thread
+ * @return 0 in case of success or -1 in case of error
+ */
 static int start_one_thread()
 {
-	struct thread *t;
+	pthread_t tid;
 	int rc;
 
-	assert(started < allowed);
-
-	t = &threads[started++];
-	t->stop = 0;
-	rc = pthread_create(&t->tid, NULL, thread_main_loop, t);
+	rc = pthread_create(&tid, NULL, thread_starter, NULL);
 	if (rc != 0) {
-		started--;
-		errno = rc;
+		/* errno = rc; */
 		WARNING("not able to start thread: %m");
 		rc = -1;
 	}
 	return rc;
 }
 
-int jobs_queue(
-		void *group,
+/**
+ * Queues a new asynchronous job represented by 'callback' and 'arg'
+ * for the 'group' and the 'timeout'.
+ * Jobs are queued FIFO and are possibly executed in parallel
+ * concurrently except for job of the same group that are
+ * executed sequentially in FIFO order.
+ * @param group    The group of the job or NULL when no group.
+ * @param timeout  The maximum execution time in seconds of the job
+ *                 or 0 for unlimited time.
+ * @param callback The function to execute for achieving the job.
+ *                 Its first parameter is either 0 on normal flow
+ *                 or the signal number that broke the normal flow.
+ *                 The remaining parameter is the parameter 'arg1'
+ *                 given here.
+ * @param arg      The second argument for 'callback'
+ * @param start    The start mode for threads
+ * @return 0 in case of success or -1 in case of error
+ */
+static int queue_job(
+		const void *group,
 		int timeout,
 		void (*callback)(int, void*),
-		void *arg)
+		void *arg,
+		enum start_mode start_mode)
 {
-	return jobs_queue3(group, timeout, (void(*)(int,void*,void*,void*))callback, arg, NULL, NULL);
-}
+	struct job *job;
+	int rc, busy;
 
-int jobs_queue2(
-		void *group,
-		int timeout,
-		void (*callback)(int, void*, void*),
-		void *arg1,
-		void *arg2)
-{
-	return jobs_queue3(group, timeout, (void(*)(int,void*,void*,void*))callback, arg1, arg2, NULL);
-}
+	pthread_mutex_lock(&mutex);
 
-/* queue the job to the 'callback' using a separate thread if available */
-int jobs_queue3(
-		void *group,
-		int timeout,
-		void (*callback)(int, void*, void *, void*),
-		void *arg1,
-		void *arg2,
-		void *arg3)
-{
-	const char *info;
-	struct job *job;
-	int rc;
+	/* check availability */
+	if (remaining_job_count <= 0) {
+		ERROR("can't process job with threads: too many jobs");
+		errno = EBUSY;
+		goto error;
+	}
 
 	/* allocates the job */
-	job = malloc(sizeof *job);
-	if (job == NULL) {
-		errno = ENOMEM;
-		info = "out of memory";
+	job = job_create(group, timeout, callback, arg);
+	if (!job)
 		goto error;
-	}
 
 	/* start a thread if needed */
-	pthread_mutex_lock(&mutex);
-	if (remains == 0) {
-		errno = EBUSY;
-		info = "too many jobs";
-		goto error2;
-	}
-	if (started == running && started < allowed) {
+	busy = busy_thread_count == started_thread_count;
+	if (start_mode != Start_Lazy
+	 && busy
+	 && (start_mode == Start_Urgent || remaining_job_count + started_thread_count < allowed_job_count)
+	 && started_thread_count < allowed_thread_count) {
+		/* all threads are busy and a new can be started */
 		rc = start_one_thread();
-		if (rc < 0 && started == 0) {
-			/* failed to start threading */
-			info = "can't start first thread";
+		if (rc < 0 && started_thread_count == 0) {
+			ERROR("can't start initial thread: %m");
 			goto error2;
 		}
+		busy = 0;
 	}
 
-	/* fills and queues the job */
-	job->group = group;
-	job->timeout = timeout;
-	job->callback = callback;
-	job->arg1 = arg1;
-	job->arg2 = arg2;
-	job->arg3 = arg3;
-	job->blocked = 0;
+	/* queues the job */
 	job_add(job);
-	pthread_mutex_unlock(&mutex);
+
+	/* wakeup an evloop if needed */
+	if (busy)
+		evloop_wakeup();
 
 	/* signal an existing job */
 	pthread_cond_signal(&cond);
+	pthread_mutex_unlock(&mutex);
 	return 0;
 
 error2:
-	pthread_mutex_unlock(&mutex);
-	free(job);
+	job->next = first_free_job;
+	first_free_job = job;
 error:
-	ERROR("can't process job with threads: %s, %m", info);
+	pthread_mutex_unlock(&mutex);
 	return -1;
 }
 
-/* initialise the threads */
-int jobs_init(int allowed_count, int start_count, int waiter_count)
+/**
+ * Queues a new asynchronous job represented by 'callback' and 'arg'
+ * for the 'group' and the 'timeout'.
+ * Jobs are queued FIFO and are possibly executed in parallel
+ * concurrently except for job of the same group that are
+ * executed sequentially in FIFO order.
+ * @param group    The group of the job or NULL when no group.
+ * @param timeout  The maximum execution time in seconds of the job
+ *                 or 0 for unlimited time.
+ * @param callback The function to execute for achieving the job.
+ *                 Its first parameter is either 0 on normal flow
+ *                 or the signal number that broke the normal flow.
+ *                 The remaining parameter is the parameter 'arg1'
+ *                 given here.
+ * @param arg      The second argument for 'callback'
+ * @return 0 in case of success or -1 in case of error
+ */
+int jobs_queue(
+		const void *group,
+		int timeout,
+		void (*callback)(int, void*),
+		void *arg)
+{
+	return queue_job(group, timeout, callback, arg, Start_Default);
+}
+
+/**
+ * Queues lazyly a new asynchronous job represented by 'callback' and 'arg'
+ * for the 'group' and the 'timeout'.
+ * Jobs are queued FIFO and are possibly executed in parallel
+ * concurrently except for job of the same group that are
+ * executed sequentially in FIFO order.
+ * @param group    The group of the job or NULL when no group.
+ * @param timeout  The maximum execution time in seconds of the job
+ *                 or 0 for unlimited time.
+ * @param callback The function to execute for achieving the job.
+ *                 Its first parameter is either 0 on normal flow
+ *                 or the signal number that broke the normal flow.
+ *                 The remaining parameter is the parameter 'arg1'
+ *                 given here.
+ * @param arg      The second argument for 'callback'
+ * @return 0 in case of success or -1 in case of error
+ */
+int jobs_queue_lazy(
+		const void *group,
+		int timeout,
+		void (*callback)(int, void*),
+		void *arg)
+{
+	return queue_job(group, timeout, callback, arg, Start_Lazy);
+}
+
+/**
+ * Queues urgently a new asynchronous job represented by 'callback' and 'arg'
+ * for the 'group' and the 'timeout'.
+ * Jobs are queued FIFO and are possibly executed in parallel
+ * concurrently except for job of the same group that are
+ * executed sequentially in FIFO order.
+ * @param group    The group of the job or NULL when no group.
+ * @param timeout  The maximum execution time in seconds of the job
+ *                 or 0 for unlimited time.
+ * @param callback The function to execute for achieving the job.
+ *                 Its first parameter is either 0 on normal flow
+ *                 or the signal number that broke the normal flow.
+ *                 The remaining parameter is the parameter 'arg1'
+ *                 given here.
+ * @param arg      The second argument for 'callback'
+ * @return 0 in case of success or -1 in case of error
+ */
+int jobs_queue_urgent(
+		const void *group,
+		int timeout,
+		void (*callback)(int, void*),
+		void *arg)
+{
+	return queue_job(group, timeout, callback, arg, Start_Urgent);
+}
+
+/**
+ * Internal helper function for 'jobs_enter'.
+ * @see jobs_enter, jobs_leave
+ */
+static void enter_cb(int signum, void *closure)
+{
+	struct sync *sync = closure;
+	sync->enter(signum, sync->arg, (void*)&sync->thread);
+}
+
+/**
+ * Internal helper function for 'jobs_call'.
+ * @see jobs_call
+ */
+static void call_cb(int signum, void *closure)
 {
-	threads = calloc(allowed_count, sizeof *threads);
-	if (threads == NULL) {
-		errno = ENOMEM;
-		ERROR("can't allocate threads");
+	struct sync *sync = closure;
+	sync->callback(signum, sync->arg);
+	jobs_leave((void*)&sync->thread);
+}
+
+/**
+ * Internal helper for synchronous jobs. It enters
+ * a new thread loop for evaluating the given job
+ * as recorded by the couple 'sync_cb' and 'sync'.
+ * @see jobs_call, jobs_enter, jobs_leave
+ */
+static int do_sync(
+		const void *group,
+		int timeout,
+		void (*sync_cb)(int signum, void *closure),
+		struct sync *sync
+)
+{
+	struct job *job;
+
+	pthread_mutex_lock(&mutex);
+
+	/* allocates the job */
+	job = job_create(group, timeout, sync_cb, sync);
+	if (!job) {
+		pthread_mutex_unlock(&mutex);
 		return -1;
 	}
 
-	/* records the allowed count */
-	allowed = allowed_count;
-	started = 0;
-	running = 0;
-	remains = waiter_count;
+	/* queues the job */
+	job_add(job);
+
+	/* run until stopped */
+	if (current_thread)
+		thread_run_internal(&sync->thread);
+	else
+		thread_run_external(&sync->thread);
+	pthread_mutex_unlock(&mutex);
+	if (sync->thread.leaved)
+		return 0;
+	errno = EINTR;
+	return -1;
+}
+
+/**
+ * Enter a synchronisation point: activates the job given by 'callback'
+ * and 'closure' using 'group' and 'timeout' to control sequencing and
+ * execution time.
+ * @param group the group for sequencing jobs
+ * @param timeout the time in seconds allocated to the job
+ * @param callback the callback that will handle the job.
+ *                 it receives 3 parameters: 'signum' that will be 0
+ *                 on normal flow or the catched signal number in case
+ *                 of interrupted flow, the context 'closure' as given and
+ *                 a 'jobloop' reference that must be used when the job is
+ *                 terminated to unlock the current execution flow.
+ * @param closure the argument to the callback
+ * @return 0 on success or -1 in case of error
+ */
+int jobs_enter(
+		const void *group,
+		int timeout,
+		void (*callback)(int signum, void *closure, struct jobloop *jobloop),
+		void *closure
+)
+{
+	struct sync sync;
+
+	sync.enter = callback;
+	sync.arg = closure;
+	return do_sync(group, timeout, enter_cb, &sync);
+}
+
+/**
+ * Unlocks the execution flow designed by 'jobloop'.
+ * @param jobloop indication of the flow to unlock
+ * @return 0 in case of success of -1 on error
+ */
+int jobs_leave(struct jobloop *jobloop)
+{
+	struct thread *t;
 
-	/* start at least one thread */
 	pthread_mutex_lock(&mutex);
-	while (started < start_count && start_one_thread() == 0);
+	t = threads;
+	while (t && t != (struct thread*)jobloop)
+		t = t->next;
+	if (!t) {
+		errno = EINVAL;
+	} else {
+		t->leaved = 1;
+		t->stop = 1;
+		if (t->waits)
+			pthread_cond_broadcast(&cond);
+		else
+			evloop_wakeup();
+	}
+	pthread_mutex_unlock(&mutex);
+	return -!t;
+}
+
+/**
+ * Calls synchronously the job represented by 'callback' and 'arg1'
+ * for the 'group' and the 'timeout' and waits for its completion.
+ * @param group    The group of the job or NULL when no group.
+ * @param timeout  The maximum execution time in seconds of the job
+ *                 or 0 for unlimited time.
+ * @param callback The function to execute for achieving the job.
+ *                 Its first parameter is either 0 on normal flow
+ *                 or the signal number that broke the normal flow.
+ *                 The remaining parameter is the parameter 'arg1'
+ *                 given here.
+ * @param arg      The second argument for 'callback'
+ * @return 0 in case of success or -1 in case of error
+ */
+int jobs_call(
+		const void *group,
+		int timeout,
+		void (*callback)(int, void*),
+		void *arg)
+{
+	struct sync sync;
+
+	sync.callback = callback;
+	sync.arg = arg;
+
+	return do_sync(group, timeout, call_cb, &sync);
+}
+
+/**
+ * Ensure that the current running thread can control the event loop.
+ */
+void jobs_acquire_event_manager()
+{
+	struct thread lt;
+
+	/* ensure an existing thread environment */
+	if (!current_thread) {
+		memset(&lt, 0, sizeof lt);
+		current_thread = &lt;
+	}
+
+	/* lock */
+	pthread_mutex_lock(&mutex);
+
+	/* creates the evloop on need */
+	if (!evmgr)
+		evmgr_create(&evmgr);
+
+	/* acquire the event loop under lock */
+	if (evmgr)
+		evloop_acquire();
+
+	/* unlock */
 	pthread_mutex_unlock(&mutex);
 
-	/* end */
-	return -(started != start_count);
+	/* release the faked thread environment if needed */
+	if (current_thread == &lt) {
+		/*
+		 * Releasing it is needed because there is no way to guess
+		 * when it has to be released really. But here is where it is
+		 * hazardous: if the caller modifies the eventloop when it
+		 * is waiting, there is no way to make the change effective.
+		 * A workaround to achieve that goal is for the caller to
+		 * require the event loop a second time after having modified it.
+		 */
+		NOTICE("Requiring event manager/loop from outside of binder's callback is hazardous!");
+		if (verbose_wants(Log_Level_Info))
+			sig_monitor_dumpstack();
+		evloop_release();
+		current_thread = NULL;
+	}
 }
 
-/* terminate all the threads and all pending requests */
-void jobs_terminate()
+/**
+ * Enter the jobs processing loop.
+ * @param allowed_count Maximum count of thread for jobs including this one
+ * @param start_count   Count of thread to start now, must be lower.
+ * @param waiter_count  Maximum count of jobs that can be waiting.
+ * @param start         The start routine to activate (can't be NULL)
+ * @return 0 in case of success or -1 in case of error.
+ */
+int jobs_start(
+	int allowed_count,
+	int start_count,
+	int waiter_count,
+	void (*start)(int signum, void* arg),
+	void *arg)
 {
-	int i, n;
+	int rc, launched;
 	struct job *job;
 
-	/* request all threads to stop */
+	assert(allowed_count >= 1);
+	assert(start_count >= 0);
+	assert(waiter_count > 0);
+	assert(start_count <= allowed_count);
+
+	rc = -1;
 	pthread_mutex_lock(&mutex);
-	allowed = 0;
-	n = started;
-	for (i = 0 ; i < n ; i++)
-		threads[i].stop = 1;
-
-	/* wait until all thread are terminated */
-	while (started != 0) {
-		/* signal threads */
-		pthread_mutex_unlock(&mutex);
-		pthread_cond_broadcast(&cond);
-		pthread_mutex_lock(&mutex);
 
-		/* join the terminated threads */
-		for (i = 0 ; i < n ; i++) {
-			if (threads[i].tid && threads[i].ended) {
-				pthread_join(threads[i].tid, NULL);
-				threads[i].tid = 0;
-				started--;
-			}
+	/* check whether already running */
+	if (current_thread || allowed_thread_count) {
+		ERROR("thread already started");
+		errno = EINVAL;
+		goto error;
+	}
+
+	/* records the allowed count */
+	allowed_thread_count = allowed_count;
+	started_thread_count = 0;
+	busy_thread_count = 0;
+	remaining_job_count = waiter_count;
+	allowed_job_count = waiter_count;
+
+	/* start at least one thread: the current one */
+	launched = 1;
+	while (launched < start_count) {
+		if (start_one_thread() != 0) {
+			ERROR("Not all threads can be started");
+			goto error;
 		}
+		launched++;
 	}
+
+	/* queue the start job */
+	job = job_create(NULL, 0, start, arg);
+	if (!job)
+		goto error;
+	job_add(job);
+
+	/* run until end */
+	thread_main();
+	rc = 0;
+error:
 	pthread_mutex_unlock(&mutex);
-	free(threads);
-
-	/* cancel pending jobs */
-	while (first_job) {
-		job = first_job;
-		first_job = job->next;
-		sig_monitor(0, job_cancel, job);
-		free(job);
-	}
+	if (exit_handler)
+		exit_handler();
+	return rc;
 }
 
+/**
+ * Exit jobs threads and call handler if not NULL.
+ */
+void jobs_exit(void (*handler)())
+{
+	struct thread *t;
+
+	/* request all threads to stop */
+	pthread_mutex_lock(&mutex);
+
+	/* set the handler */
+	exit_handler = handler;
+
+	/* stops the threads */
+	t = threads;
+	while (t) {
+		t->stop = 1;
+		t = t->next;
+	}
+
+	/* wake up the threads */
+	evloop_wakeup();
+	pthread_cond_broadcast(&cond);
+
+	/* leave */
+	pthread_mutex_unlock(&mutex);
+}